Extraction and noncondensing turbine arrangement



2 1 2-- H. w.-cRoss EILAL Q,

EXTRACTION AND NONCONDENSINGITURBINE ARRANGEMENT Filed June, 28, 1939 Invent oT-s'. Harold W.Cr-os .EdwinSAfVellsJrr,

TheifAtfiorr-wey Patented Nov. 24, 1942 EXTRACTION ANDVNONCONDENSING TURBINE ARRANGEMENT Harold W. Cross, Hinsdale, and Edwin s. Wells,

Jr., River Forest, lll., assignors .to General Electrio Company, a corporation of New York Application June 28, 1939, Serial No. 281,550

1 Claim.

The present invention relates to extraction and non-condensing turbine arrangements which in clude a turbine having an intermediate or last stage from which elastic fluid is supplied to a consumer for power generation, heating, proc-- essing or like industrial purposes at a predetermined temperature or pressure.

' The object of our invention is to provide an improved construction and arrangement of tinbine plants whereby better economy and efficiency are attained.

In extraction and non-condensing turbine plants for supplying steam or like elastic-fluid from an intermediate or. last stage at a certain temperature, it was the practice heretofore to choose an initial elastic fluid condition, that is,

the turbine is definitely limited. Ordinarily the extraction 'and non-condensing turbines are arranged to drive an electric generator or generators. The electrical output of such generators depends upon the temperature and pressure drop across the turbine and in case the inlet temperature and the extraction or exhaust temperatures of the turbine are fixed with regard to the temperature required for processing. heating' or like purposes. the electrical output of the generator is limited accordingly.

We have found that a considerable gain in electrical output from the high pressure. noncondensing portion of such a cycle can be realized by increasing the total steam temperature at the throttle, that is, at the inlet of the turbine. The electrical output is definitely established by the energy drop between the initial and exhaust conditions and by the quantity of steam flow through the turbine. By increasing the total steam temperature at the throttle for a given steam pressure the available energy between initial and exhaust conditions is increased and with it the electrical output of the generator is increased accordingly. However, the increase in initial temperature causes a correspending increase of the temperature at the ex- I haust or extraction stage and results in a temperature that is higher than desired. 7

According to our invention the temperature at the exhaust or extraction stage is reduced by the provision of a heat exchanger in the form of a de-superheater. w p

In some instances of this kind it has beenthe practice to install a feed Water heater supplied with steam or like elastic fluid from the exhaust or extraction stage of the turbine in order to obtain a greater electrical output by utilizing more heat from the exhaust steam, thereby increasing the flow of steam through thehigh pressure unit. The gain thus obtained is further I increased according to our invention by theprovision of a combined de-superheater and feed water heater connected in series to the exhaust or extraction stage of the turbine and by in:- creasing the turbine inlet temperature accord ingly. In a preferred embodiment the combined de-superheater and feed water heater is arranged in two sections, one section in the form of a surface type heat exchanger designed onv the counterflow principle and arranged for free flow of exhaust or extraction steam through it and the other section in the form of a condensation type feed water heater connected in series with the de-superheater. A supply conduit for process steam is connected to receive steam from points ahead and behind the de-superheater.

For a better understanding of what we believe to be novel and our invention, attentionis directed to the following description and" the claim appended thereto in connection with the accompanying drawing.

The single figure of the drawing illustrates diagrammatically a non-condensing steam tur bine arrangement embodying our invention. H

The arrangement comprises a boiler Hi hav: ing a discharge conduit H for supplying steam to a turbine I 2 having a throttle valve I3 and being coupled to drive an electric generator 14. The exhaust of the turbine I2 is conducted by a conduit E5 to a surface type de-superheater IS having a de-superheating coil IT. The desuperheated steam is conducted by a conduit l8 from the de-superheater IE to a feed water heater I9 which is also of the surface type including cooling tubes 20 connected between headers 2| and 22. Cooling medium, in the present instance feedwater, is forced into the feed Water heater I!) by means including a conduit 23 connected to the header 2! and discharged from the header 22 through a conduit 24 to the inlet of the desuperheating element ll. During operation part of the steam discharged from the turbine I2 is de-superheated in the de-superheater l6 and thereafter condensed in the feed water heater l9. The condensate is discharged from the latter element as regards the feed water supply is connected by a conduit 26 to the inlet of the boiler. In order to permit regulation of the feed water temperature in the conduit 26 a bypass 21 is provided for bypassing some of the feed water with respect to the feed water heater l9. This con-- duit 21 is connected between the feed water supply conduit 23 and the feed water discharge conduit 24 and includes a valve 28. In the present amount of steam flowing from the turbine discharge conduit |5 directly into the conduit 3|, resulting in a decrease in temperature. This decrease will continue until the desired temperature is attained. Vice-versa, a drop in temperature in the conduit 3| causes opening movement of the valve 33, resultin in increased flow of superheated steam from the conduit I5 to the conduit 3 l From another viewpoint, the conduit for supplying elastic fluid from an intermediate or last W stage of a turbine to a consumer has branches instance the valve 28 has an arm 29 connected to a temperature-responsive device including abellows 30 whereby the valve is moved in response to mperature changes in the conduit 26; If the emperature in the conduit 26 increases, the bellows 30 expands, moving the valve 28 towards opening position and bypassing an increased amount of feed water throughthe conduit 21, resulting in a decrease in temperature in the conduit 26. Thus, the valve 28 is automatically controlled to maintain constant temperature in the boiler inlet conduit 26. As pointed out before, the turbine in accordance with our invention is operated at an inlet temperature which results in an exhaust temperature higher than that desired. Inorder to obtain the desired temperature some of the steam discharged by the turbine is mixed with steam discharged by the desuperheater. In the present instance a conduit 3| is connected to the turbine discharge conduit l5 for conducting exhaust steam to a consumer for processing, heating or like industrial purpose and this conduit 3| is also connected by a branch conduit 32 to the de-superheater discharge conduit I8 to receive de-superheated steam. The desuperheated steam and the superheated steam received from the turbine discharge conduit l5 mix in the conduit 3| and if properly proportioned will result in the desired temperature. The proportioning is preferably effected automatically by means including a valve in at least one of the conduits 3| and 32. In the present instance the conduit 3| includes a valve 33 which has an arm 34 connected to a temperature-responsive device 35 having a bellows 36 and-being responsive to temperature of the steam at a point of the conduit 3| behind itsjuncture with the branch conduit 32 as regards the direction of flow therethrough. During operation the increase of the temperature in the conduit 3| causes expansion of the bellows 36 whereby the valve 33 is moved towards closing position, thus reducing the connected ahead and behind the de-superheater l6 respectively. One of the branches, in the present instance the one connected ahead of the de-superheater as regards the direction of flow therethrough, includes a valve for controlling the amount of steam flowing through this branch with regard to that flowing through the other branch 32 in order to obtain the desired steam temperature at a point behind the juncture of the two branches.

Having described the method of operation of our invention, together with the apparatus which we now consider to represent the best embodiment thereof, we desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What we claim as new and desire to secure by Letters Patent of the United States is:

Turbine arrangement including the combina tion of a turbine having a stage from which fluid is to be supplied for industrial purposes, the turbine being operated at an inlet temperature at which the elastic fluid temperature in said stage is higher than desired for industrial purposes, a de-superheater and a feed water heater connected in series to receive fluid from said stage, means including a conduit having branches connected to the inlet and the outlet respectively of the de-superheater, means for automatically controlling the ratio of flow through saidbranches in response to temperature changes of the fluid in said conduit, the de-superheater and the feed water heater being of the surface type and having cooling elements connected in series, a conduit for conducting feed water to the feed water heater, a bypass connected between said conduit and the cooling element of the de-superheater for bypassing some of the feed water with respect to the feed water heater, and means including a valve in the bypass for automatically controlling the flow therethrough in response to changes of the temperature of the feed water discharged from the desuperheater.

| HAROLD W. CROSS.

EDWIN s. WELLS, JR. 

